Laboratory testing is probably the most common clinical routine performed in modern medical care. Cerebral spinal fluid and urine may be used for biochemical analysis, however blood is the body fluid mostly used and these tests are highly important diagnostic and prognostic tools in the everyday patient care.
Laboratory testing could be divided into three phases.                The pre analytic phase: all steps before the actual analysis of a sample including patient variables, collection, handling and processing        The analytic phase        The post analytic phase: test reporting variables        
Obviously it is of great importance that all three phases are performed correctly since errors could give misleading information to the physicians and therefore jeopardize the well-being of individuals or groups of patients. A majority of the errors seen in laboratory testing occurs in the pre analytic phase, and hemolysis is one of the most significant causes for rejection of specimen. Hemolysis is typically understood as the release of hemoglobin and other intracellular components from erythrocytes to the surrounding plasma, following damage or disruption of the cell membrane. Hemolysis may occur either in vivo or in vitro, and is a most undesirable condition that influences the accuracy and reliability of laboratory testing. Reasons to why hemolysis interferes with multiple biochemical analysis may be e.g. that hemoglobin interferes with the measurements (e.g. spectrophotometric methods), and also that the release of biochemical markers from the broken red blood cells causes false high values of these substances.
Visible hemolysis, as a hallmark of a more generalized process of blood cell damage, is usually not apparent until the separation of serum or plasma has occurred. It is commonly defined as an extracellular hemoglobin concentration of above 0.3 g/L (0.0186 mmol/L), resulting in a detectable pink-to-red hue of serum or plasma.
Generally a collected blood sample needs to be transferred to a distant department where red blood cells are separated from the plasma or serum, for instance by means of centrifugation, and said hue may be detected and reported to the staff in charge of the patient.
Modern laboratories also objectively assess the degree of hemolysis in every blood sample coming in for analysis. If the hemolysis is substantial enough to cause clinically relevant interference to the analysis the result is not reported and a new samples has to be collected from the patient. Obviously the above described procedures for assessing the validity of the specimen is related to a time delay causing an undesirable situation for the patient as well as leading to circuitous routines.
Alternative detection methods have been suggested, for instance in WO96/23223 which describes a method and apparatus for detecting hemolysis from a blood sample which may be used in a non-laboratory environment. However the detection procedure according to WO96/23223 requires a series of time consuming and inefficient steps leading to a laborious procedure and undesired interruptions.